On 10/24/05, Thomas Garner <tlg1466@xxxxxxxxxxxx> wrote: > Should there be any consideration for the utilization of the gigabit > interface that is passing all of this backup traffic, as well as the > speed of the drive that is doing all of the writing during this > transaction? Is the 18MB/s how fast the data is being copied over the > network, or is it some metric within the host system? The switched gigabit network is plenty fast. The bottleneck is reading from the RAID1 while it is under contention. Here are measurements from transferring a chunk of data from /dev/zero, a single unmounted drive, and RAID1. Measurements are reported by dd_rescue and reflect how fast data is moving over the network. I was careful to use smart command line options with dd_rescue, avoid contaminating Linux's disk cache, and make sure results were repeatable. MB/s Operation ==== ============================ 72.0 dd-rescue /dev/zero - | netcat 61.8 dd-rescue [unmounted single drive] - | netcat 18.8 dd-rescue md0 - | netcat dd_rescue v1.11 options: -B 4096 -q -l -d -s 11G -m 200M -S 0 - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
